如何将带有正则表达式的配置单元查询转换为 oracle

Question

我有这段文字：

Process explanation:The bottle is then melted to form liquid glass;Final activity for manager:Labeling of previous samples

我只想得到'Process explanation'之后的部分，但不包括'final activity...'

像这样：

The bottle is then melted to form liquid glass.

这是我要转换为 oracle 的当前配置单元查询：

SELECT REGEXP_EXTRACT(
               'Process explanation:The bottle is then melted to form liquid glass;Final activity for manager:Labeling of previous samples',
               '.*(process[ \t]*(explanation)?[ \t]*:[ \t]*)(.*?)([ \t]*;[ \t]*final[ \t]+activity[ \t]+for[ \t]+manager.*$|$)',
               3) as extracted
FROM my_table

Answer 1

如果这些子字符串就像您所说的那样，那么有一个非常简单的选项 - substr + instr 函数。

SQL> with test (col) as
  2    (select 'Process explanation:The bottle is then melted to form liquid glass;Final activity for manager:Labeling of previous samples' from dual)
  3  select substr(col, instr(col, 'Process explanation') + length('Process explanation') + 1,
  4                     instr(col, 'Final activity') - instr(col, 'Process explanation') -
  5                       length('Process explanation') - 2
  6               ) result
  7  from test;

RESULT
----------------------------------------------
The bottle is then melted to form liquid glass

SQL>

Answer 2

我想到了这样的事情：

with strings as
(SELECT '1Process explanation:The bottle is then melted to form liquid glass;Final activity for manager:Labeling of previous samples' str FROM DUAL
union all
SELECT '2Process explanation:The bottle is then melted to form liquid glass;' str FROM DUAL
union all
SELECT '3Process :The bottle is then melted to form liquid glass' str FROM DUAL
union all
SELECT '4Process explanation: plasma gasification combined with centrifugal activity' str FROM DUAL
union all
SELECT '5Final activity for manager:Labeling of previous samples' str FROM DUAL
)
SELECT str
, REGEXP_SUBSTR(
               str,
           '(.*process[[:blank:]]*(explanation)?[[:blank:]]*:[[:blank:]]*)([A-Za-z0-9 ]*)([[:blank:]]*;[[:blank:]]*final[[:blank:]]*activity[[:blank:]]*for[[:blank:]]*manager.*$)?',
           1, 1, 'i',3)
                as extracted
FROM strings

导致：

STR	EXTRACTED
1Process explanation:The bottle is then melted to form liquid glass;Final activity for manager:Labeling of previous samples	The bottle is then melted to form liquid glass
2Process explanation:The bottle is then melted to form liquid glass;	The bottle is then melted to form liquid glass
3Process :The bottle is then melted to form liquid glass	The bottle is then melted to form liquid glass
4Process explanation: plasma gasification combined with centrifugal activity	plasma gasification combined with centrifugal activity
5Final activity for manager:Labeling of previous samples	-

假设匹配空白组而不是你的 space 和选项卡列表 [ \t] 是可以的。编辑：稍微修改了正则表达式，因为最后一组可能为空 '.*' 一直捕获整行。

如何将带有正则表达式的配置单元查询转换为 oracle

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